These files are part of the dataset "Historical built-up intensity layer series for the U.S. 1810 � 2015,"
contained in the dataverse �HISDAC-US: Historical Settlement Data Compilation for the United States� 
(https://dataverse.harvard.edu/dataverse/hisdacus).

Reference:
Leyk, Stefan; Uhl, Johannes H., 2018, "Historical built-up intensity layer series for the U.S. 1810 - 2015," 
https://doi.org/10.7910/DVN/1WB9E4, Harvard Dataverse

Related Publication:
Leyk, Stefan; Uhl, Johannes H., 2018, "HISDAC-US: Historical Settlement Data Compilation for the Conterminous United States Over 200 Years," Scientific Data 5:180175
https://doi.org/10.1038/sdata.2018.175

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Corrigendum:

In the original version 1.0 the unit for the BUI layers was described as square meters but the raster values were computed in square feet. 
This has been corrected in this new version and the raster values of all BUI layers are now correctly calculated in square meters.

Furthermore, the spatial reference system used to project the layers was incorrectly described in version 1.0. This has been corrected in this new version (see below).
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This dataset contains the following files:

- BUI.tar.gz: Archive contains the time series of BUI raster layers between 1810 and 2015 (BUI_1810 � BUI_2015) with semi-decadal temporal resolution.
- BUI_IPU.tar.gz: Archive contains IPU raster time series [1810-2015] accompanying BUI
- BUI_OPU.tar.gz: Archive contains OPU raster time series [1810-2015] accompanying BUI
- BUI_OPPU.tar.gz: Archive contains OPPU raster time series [1810-2015] accompanying BUI 
- TPixMiss.tar.gz: Archive contains the raster layer representing the number of missing built year records per pixel
- APixMiss.tar.gz: Archive contains the raster time series [1810-2015] representing the number of missing building area records per pixel

Abbreviations and explanations:
BUI:		Built-up intensity. Integer-valued raster datasets containing indoor building gross area sum per pixel area in square meters.
IPU:		Inside positional uncertainty. A relative positional uncertainty measure describing the likelihood of a record located within the pixel area to be outside.
OPU:		Outside positional uncertainty. A relative positional uncertainty measure describing the likelihood of a record located outside the pixel area to be inside.
OPPU:		Overall positional uncertainty. Per-pixel average of IPU and OPU.

Data source: Zillow Transaction and Assessment Dataset (ZTRAX) (c) Zillow Inc.
Spatial resolution: 250m
Coordinate reference system:
USA Contiguous Albers Equal Area Conic USGS version (SR-ORG:7480)
https://spatialreference.org/ref/sr-org/usa_contiguous_albers_equal_area_conic_usgs_version-2/
Proj4: +proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23.0 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m +no_defs

Contact:
Stefan Leyk
Department of Geography
University of Colorado Boulder
GUGG 110, 260 UCB 
Boulder, CO 80309-0260, United States of America
stefan.leyk@colorado.edu